Ignition wire

Abstract

Automotive ignition wire with a high temperature rating, excellent electrical insulating properties, heat resistance, oil resistance and abrasion resistance is described. The wire utilizes a conductor made up of either a helically wound metal conductor on a radio frequency insulating polymer overcoated on a polymer adhesive layer on a glass fiber bundle; or a glass fiber-cotton fiber braid on a graphite impregnated glass layer. Overcoating either one of the conductors is a semiconducting polymer layer, an ethylene-propylene-diene monomer containing polymer layer optionally overcoated with a glass braid layer and a polymer jacket material. The polymer jacket material comprises a polymeric mixture of ethylene vinyl acetate and ethylene-propylene-diene monomer stabilized with a mixture of a phenolic antioxidant and a metal salt antioxidant.

We claim: 
     
       1. Electrically conductive ignition wire comprising a glass fiber core overcoated with an adhesion promoting polymer layer, which is overcoated with a radio frequency insulating polymer, having helically wrapped thereon electrically conducting wire, which is overcoated with a layer of ethylene-propylene-diene monomer containing polymer, and a polymer jacket coated on the ethylene-propylene-diene monomer containing polymer layer, the polymer jacket comprising a mixture of ethylene-propylene-diene monomer containing polymer with ethylene vinyl acetate, stabilized with a mixture of phenolic antioxidant and a metal salt antioxidant. 
     
     
       2. Electrically conductive ignition wire comprising a graphite impregnated glass fiber core overbraided with a glass and cotton fiber braid, which is overcoated with a semiconducting polymer layer containing release agent, a layer of ethylene-propylene-diene monomer containing polymer coated on the semiconducting polymer layer, and a polymer jacket layer coated over the ethylene-propylene-diene monomer containing polymer layer, the polymer jacket comprising a mixture of ethylene-propylene-diene monomer containing polymer with ethylene vinyl acetate stabilized with a mixture of a phenolic antioxidant and a metal salt antioxidant. 
     
     
       3. The wire of claim 1 which additionally contains a layer of glass fiber braid between the ethylene-propylene-diene monomer containing polymer layer and the polymer jacket. 
     
     
       4. The wire of claim 2 which additionally contains a layer of glass fiber braid between the ethylene-propylene-diene monomer containing polymer layer and the polymer jacket. 
     
     
       5. The wire of claims 1, 2, 3 or 4 wherein the ethylene vinyl acetate polymer contains 40% by weight vinyl acetate and the antioxidant mixture is present in an amount of about 3.5% by weight and the weight ratio of phenolic antioxidant to metal salt antioxidant is about 1:2.